There is conventionally known single facer apparatus which forms a single-faced corrugated board by corrugating a sheet medium so as to have corrugations having a predetermined pitch size, and adhering a liner upon the crests of the corrugations by means of a suitable adhesive. The single facer comprises a radially outer fluted roll and a radially inner fluted roll both having a wavy set of flutes upon the circumferential portions thereof and rotatably supported upon a frame in such a manner that their fluted circumferences may be engaged in a vertical relationship, and a press roll which is designed to be brought into press contact with the radially inner fluted roll with the corrugating medium and liner interposed therebetween. The corrugated medium is formed with predetermined flutes or corrugations as it is fed between the radially outer fluted roll and the radially inner fluted roll as a result of the engagement of their fluted circumferences, and in addition glue is applied to the crests of the corrugations by means of a gluing roll provided within a gluing mechanism. The liner being fed from the opposite side of the corrugated medium with respect to the press roll is bonded to the crests of the corrugated medium being pressed against the radially inner fluted roll by means of the press roll as the corrugated medium passes between the radially inner fluted roll and the press roll so as to form a single-faced corrugated board.
Single-faced corrugated boards are generally classified into Flute A, Flute B, Flute C, Flute E, Nos. 4 and 5 Flutes, and the like, depending upon the depth of the flutes to be formed upon the corrugated medium and the standard number of crests per 30 cm. Such flute types can be selected depending upon the shapes of the fluted circumferences of the radially outer and radially inner fluted rolls to be disposed within the single facer.
As described above, there are many flute types within a single-faced corrugated board and the corrugation type is dependent upon the shape of the flutes formed upon the surface of the radially outer and radially inner fluted rolls incorporated within the single facer. Accordingly, in order to form different types of single-faced corrugated boards within one single facer, there has been employed a manufacturing system wherein a plurality of single facers are arranged along a corrugator line so as to enable selective shifting to the desired single facer.
In this case, however, the installation of a plurality of single facers involves various problems for practical applications including the installation area, workability and incidental equipment, while it is also known that the cost of the apparatus is substantially doubled. Moreover, the combination of the types of single-faced corrugated boards with different types of corrugations selectively made during the production is not random but predetermined for example, a combination of Flutes A and E, or Flutes B and E, or Flutes C and E, and the like. Then, various types of machines for making several kinds of single-faced corrugated boards with different types of corrugations are proposed, in which two pairs of fluted roll units each having fluted rolls with different types of flutes disposed within one single facer so as to form different types of single-faced corrugated boards are utilized.
For example, there is a preceding patent application filed by means of the present applicant and entitled: "Single facer", Japanese Provisional Patent Publication No. 58881/1986. In the apparatus according to such invention, as disclosed in the published drawings, the first fluted roll unit consisting of a pair of fluted rolls and the second fluted roll unit composed of a pair of fluted rolls are arranged diagonally above and below the press roll, respectively, which can selectively be used in conjunction with either one of the two fluted roll units, and the combination of either the press roll and the first fluted roll unit or the press roll and the second fluted roll unit is selected before operation of the apparatus so as to form the single-faced corrugated boards with a different form of corrugation.
In accordance with this system, when the combination of corrugated board sheets is to be changed by means of a different combination or selection of corrugating rolls or when the ordinary production of corrugated boards becomes impossible due to worn fluted rolls, all of the radially outer and radially inner rolls of the first and second fluted roll units must be replaced with other new rolls. In this case, the second fluted roll unit arranged beneath the first fluted roll unit was disposed along an inclined plane and below the gluing mechanism, so that the replacement work of its radially outer and radially inner rolls was very difficult requiring much labor and time. This has been a new problem to be solved.